The product $(a+b)(c+d)$
Practice
Expand and simplify.
*Write your answers with powers of $x$ in descending order. $\left(\square x^2 \pm \square x \pm \square\right)$
$\left(x+1\right)\left(x+8\right)$
$\left(x+8\right)\left(x-8\right)$
$\left(-x+5\right)\left(3-x\right)$
$\left(x+4\right)\left(3-x\right)$
$\left(7+x\right)\left(x-8\right)$
$\left(-3+x\right)\left(-x+9\right)$
$\left(6+x\right)\left(8+x\right)$
$\left(-2+x\right)\left(7+x\right)$
$\left(4x-9\right)\left(x-4\right)$
$\left(3x+4\right)\left(5x+7\right)$
$\left(-5x+4\right)\left(-3+2x\right)$
$\left(-5x+6\right)\left(-4+x\right)$
$\left(1+2x\right)\left(x-4\right)$
$\left(1+9x\right)\left(-x+6\right)$
$\left(3+x\right)\left(4-3x\right)$
$\left(7+x\right)\left(7-x\right)$